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Our future, our universe, and other weighty topics

Wednesday, July 20, 2016

Randomness, Survival of the Fittest, and the Origin of Biological Complexity

According
to Neo-Darwinism, the astonishing biological complexity of the
natural world arises from a combination of random mutations and
natural selection. The idea is that random mutations produce random
changes in organisms, and that natural selection (or survival of the
fittest) causes helpful random mutations to proliferate.
Neo-Darwinists maintain that this can account for the appearance of
useful complex features such as wings, eyes, elephant trunks, giraffe
necks, and so forth.

Let
us try to imagine a situation that might involve a combination of
randomness and survival of the fittest. Imagine you are a football
coach at a college or university. Every year many students sign up
for the football team, hoping to gain the on-campus prestige enjoyed
by college football players. This provides you with a great deal of
randomness. Some of these applicants will be strong, and some will be
weak. Some of the applicants will be in good physical shape, and some
will be in poor physical shape. Some will be fast, and some will be
slow.

But
where does the “survival of the fittest” come into play? That
happens with your discretionary roster cuts. Given this random pool
of applicants, you will be able to create a “survival of the
fittest” effect by cutting from the football roster any aspiring
team members who are too weak or slow or who cannot catch or pass or
punt the football.

Now
let's suppose the randomness of the applicant pool and the roster
cuts are the only factors involved. You simply take your starting
pool of aspiring football players, subject them to various physical
tests, and cut from the roster a certain number of people who fail to
perform well on the physical tests. You do nothing else. So you have
randomness, and survival of the fittest. Will this result in a
winning football team, one that produces the coordinated
functionality needed to win football games?

Of
course, it will do no such thing. Producing a winning football team
requires both design and a huge amount of coordination. The design
comes from designing particular football plays that your team will
execute. The coordination comes when particular players are assigned
particular positions, and these players repeatedly practice smoothly
coordinated football plays. Without this design and coordination,
your football team will be a mess. When a play starts, players will
just wander about, without anyone knowing whether they are supposed
to block, throw the ball, catch the ball, or punt.

So
clearly for a football coach, randomness plus survival of the fitness
does not yield coordinated functionality. But someone may argue that
this analogy is inadequate, because it only involves survival of the
fittest and does not involve the idea of differential
reproduction. Differential reproduction means that those who are
more fit to survive will reproduce more frequently, and those who are
less fit to survive will reproduce less frequently. Differential
reproduction is basically the same as natural selection, and is
actually a better term for such a thing (since nature does not
actually choose or select anything, natural selection is not a
literally accurate term, even if it may be accurate in some
figurative sense, to at least some extent).

So
let's imagine a better analogy, one that will include both randomness
and differential reproduction. Let us imagine a tall skyscraper
filled with monkeys who have been trained to type on laptop
computers. Let us imagine that each laptop has an email program or
full-screen instant messaging program on its screen. Let us imagine
that all day long the monkeys are randomly striking the keys, with
such activity being encouraged because the more typing the monkeys
do, the more food appears. (This could easily be accomplishing by
programming the laptops to count the keystrokes and send a message to
some feeding apparatus, whenever a hundred keystrokes were
detected.) The random typing of the monkeys gives us all the
randomness we could ever ask for.

But
what about the differential reproduction – how can we get that? We
can simply imagine that there is a roving editor walking around the
skyscraper, examining the laptop screens. Whenever the editor finds
a laptop screen that gives some good prose, the editor presses some
keystroke on the laptop that sends out this typed output to quite a
few other laptops in the building, via email or instant messaging. So
if the output on the laptop screen is a decent sentence, maybe such a
sentence gets transmitted to 10 other laptops, and put on the screens
of these laptops. If the output on the laptop screen is a decent
paragraph, maybe such a sentence gets transmitted to 100 other
laptops. So this is differential reproduction, a kind of natural
selection in which fortunate random output gets reproduced much more
frequently.

Will
such a system result in the large scale appearance of coordinated
complexity? Under such a system would we expect to eventually see
lots of laptop screens on which there were good poems, letters,
essays, articles, recipes, or intelligent pieces of computer code?
Absolutely not. Despite the combination of randomness and
differential reproduction, we should not expect any monkey's laptop
to have anything but gibberish on it. Even if such a system were
kept running for a billion years, we would not expect for coordinated
complexity to appear to any large degree.

We
can think of two general reasons why this would be true. The first
reason is what we may call the discarding of preliminary
implementations. If we are to imagine that our roving editor acts
like natural selection in the natural world, we must imagine that the
editor would reward only work which had received a certain level of
functional quality. So if a monkey's laptop contained a sentence such
as “I think what we should do about the gun violence problem is
nanae anowe anslweonw assfw,” such a sentence (a preliminary
implementation of a functional sentence) would not be rewarded with
increased reproduction. In order for the random output to be rewarded
with increased reproduction, it would have to have a high degree of
ordered, coordinated complexity, a level of functionality very, very
unlikely to be achieved by chance.

The
second reason why this skyscraper of typing monkeys would not result
in large-scale coordinated complexity is that in the very rare cases
in which random output produced functionality that was rewarded with
increased reproduction, the randomness of the typing monkeys would
further degrade that functionality over time. So if a monkey ever
typed a good sentence, and that sentence got transmitted to the
screens of 10 other monkeys, the subsequent random typing of those
monkeys would quickly degrade the coordinated complexity, and tend to
gradually turn it into uncoordinated gibberish.

Similar
reasons cast great doubt on the claim that in the natural world, some
combination of random mutations and natural selection can produce
coordinated complexity. The discarding of preliminary
implementations is something we should expect to be constantly
occurring in a natural world ruled by blind chance. For example, if
an eyeless organism started to develop a light-sensitive dimple that
could be the start of an eye, we would expect natural selection to
throw away such a useless feature – unless by some incredibly
improbable coincidence it happened to have almost simultaneously arrived by
chance with other changes needed for some earliest version of
functional vision (changes such as an optic nerve conveniently
stretching from such a feature to the brain, and also quite a few
changes in the brain needed to process such visual input). To give
another example, if an organism by chance developed a wing stump, we
would expect natural selection to discard such a feature, as it would
provide no immediate benefit. The idea that natural selection will tend to
discard anything that isn't useful comes from Darwin himself.

Imagine
you are hired to work in a junkyard, and you are told to build useful
things from the odds and ends lying around. But there's a problem:
you are closely watched by a dimwitted foreman with no foresight or
imagination, a guy you nickname “the Brainless Boss.” You start
out by finding an axle and two wheels, and fit them together. You
think to yourself: this can be the start of a good wagon or cart. But
then your foreman sees what you are doing, and throws it away in the
trash bin. “Not useful – make something useful,” the foreman
says. You then find some wood, and nail together three pieces of wood
to make a U-shape. You think to yourself: this can be the start of a
bookshelf. But your foreman arrives, and throws what you have made
into the trash bin. “Not useful – make something useful,” the
foreman says. You realize that your chance of making anything useful
are not good, because the “Brainless Boss” will always be
discarding your preliminary implementations. So it would be in the
natural world ruled only by chance and natural selection. Lacking
any foresight or imagination, natural selection would always be
acting like this “Brainless Boss,” discarding preliminary
implementations that were not yet useful.

Similarly,
in the natural world we would expect that random mutations would
vastly more often degrade coordinated functionality than to improve
it. The more complex and coordinated a piece of functionality is,
the more likely it will be that random changes will degrade it rather
than improve it. For example, random changes in computer code will
be 100 times more likely to harm the code than to help it.

Part
of the appeal of Neo-Darwinism is its simplicity. Neo-Darwinism tries
to explain the appearance of biological complexity by giving us the
real simple equation that randomness plus survival of the fittest
eventually yields astonishingly coordinated wonders of biological
complexity. The problem is that this equation is not accurate.
Randomness plus survival of the fittest does not yield coordinated
functionality. The answer to the origin of biological functionality
must be something vastly deeper or more complicated than this
simplistic little equation.

Copyright Notice

All posts on this blog are authored by Mark Mahin, and are protected by copyright. Copyright 2013-2014 by Mark Mahin. All rights reserved. Any resemblance between any fictional character and any real person is purely coincidental.